It is known to reinforce the olefin polymers by including micas therein. In order to achieve a satisfactory adhesion between the micas and the polymer in this kind of preparations, these two components are generally treated with suitable modifiers before blending with each other. Thus, the micas can be given a surface coating consisting of silanic compounds, whereas the olefin polymers can be reacted with compounds containing carboxylic acid groups, such as acrylic or maleic acid, so as to form a chemical bond between the silanic and the carboxylic group on blending at high temperature. Like methods are disclosed for instance in Japanese Patent Publication Nos. 7953157 and 80104338.
The above mentioned methods are however cumbersome and expensive, especially because they require the modification of the whole mass of polymer involved in the blend, in a preliminary and separate step.